This invention is in the field of rotating and counter rotating inertia members, or inertia gimbal drive systems.
Prior art systems employing counter rotating masses were deficient, in not being able to reduce the effective angular momentum of the system to substantially zero.
In systems employing gimbaled sensors, provision for angular scanning is generally required without introducing disturbance torques into the gimbal mounting base. Typically, momentum wheels or control moment gyros are utilized to implement the gimbal drives for these systems.
There are two particularly significant imperfections associated with such gimbal drives. Firstly, bias torques or coulomb friction and spring restraint torques that are present, ultimately give rise to angular momentum saturation of the drive thus limiting the operating time interval that can be realized before re-initiation is required. Secondly, the coulomb friction and spring restraint torques between various elements of the drive assembly are coupled to the mounting base thus producing uncompensated base disturbance torques.